Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work.

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  #1   Report Post  
Posted to rec.crafts.metalworking
Chris
 
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Default Band saw blade keeps coming off

I feel an idiot for not being able to get this damned thing fixed myself,
but I have a smallish bench mounted metal cutting bandsaw of good quality.
OK, she's done a bit of work before I got her, but there's no wear in the
bearings and the cast iron wheels run true. I have played with blade
tension (tighter seems more reliable) and with the top (none powered wheel)
tilt, which is adjustable, and the blade guide ball bearings, which are
adjustable, but STILL the blade will suddenly jump off one of the wheels. 3
things look less than perfect. the wheels had some sort o gritty coating,
when new, like coarse carborundum paper, this is now quite worn. The blade
makes a noticeable jump as the welded part passes through the work piece.
Nothing much, but when worked hard it is audible and can be felt. Finally
the blade is quite old and not as sharp as it might be. Cutting alloy makes
the blade come off more than steel.. Can anyone with experience of these
machines point me in any directions to look to? Thanks!
  #2   Report Post  
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Tom Gardner
 
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Default Band saw blade keeps coming off

The blade


"Chris" wrote in message
...
I feel an idiot for not being able to get this damned thing fixed myself,
but I have a smallish bench mounted metal cutting bandsaw of good quality.
OK, she's done a bit of work before I got her, but there's no wear in the
bearings and the cast iron wheels run true. I have played with blade
tension (tighter seems more reliable) and with the top (none powered
wheel)
tilt, which is adjustable, and the blade guide ball bearings, which are
adjustable, but STILL the blade will suddenly jump off one of the wheels.
3
things look less than perfect. the wheels had some sort o gritty coating,
when new, like coarse carborundum paper, this is now quite worn. The blade
makes a noticeable jump as the welded part passes through the work piece.
Nothing much, but when worked hard it is audible and can be felt. Finally
the blade is quite old and not as sharp as it might be. Cutting alloy
makes
the blade come off more than steel.. Can anyone with experience of these
machines point me in any directions to look to? Thanks!



  #3   Report Post  
Posted to rec.crafts.metalworking
Stephen Young
 
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Default Band saw blade keeps coming off

Chris wrote:
I feel an idiot for not being able to get this damned thing fixed myself,
but I have a smallish bench mounted metal cutting bandsaw of good quality.
OK, she's done a bit of work before I got her, but there's no wear in the
bearings and the cast iron wheels run true. I have played with blade
tension (tighter seems more reliable) and with the top (none powered wheel)
tilt, which is adjustable, and the blade guide ball bearings, which are
adjustable, but STILL the blade will suddenly jump off one of the wheels. 3
things look less than perfect. the wheels had some sort o gritty coating,
when new, like coarse carborundum paper, this is now quite worn. The blade
makes a noticeable jump as the welded part passes through the work piece.
Nothing much, but when worked hard it is audible and can be felt. Finally
the blade is quite old and not as sharp as it might be. Cutting alloy makes
the blade come off more than steel.. Can anyone with experience of these
machines point me in any directions to look to? Thanks!


Install new tires on the wheels.
  #4   Report Post  
Posted to rec.crafts.metalworking
Tom
 
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Default Band saw blade keeps coming off

Chris wrote:

I feel an idiot for not being able to get this damned thing fixed myself,
but I have a smallish bench mounted metal cutting bandsaw of good quality.
OK, she's done a bit of work before I got her, but there's no wear in the
bearings and the cast iron wheels run true. I have played with blade
tension (tighter seems more reliable) and with the top (none powered wheel)
tilt, which is adjustable, and the blade guide ball bearings, which are
adjustable, but STILL the blade will suddenly jump off one of the wheels. 3
things look less than perfect. the wheels had some sort o gritty coating,
when new, like coarse carborundum paper, this is now quite worn. The blade
makes a noticeable jump as the welded part passes through the work piece.
Nothing much, but when worked hard it is audible and can be felt. Finally
the blade is quite old and not as sharp as it might be. Cutting alloy makes
the blade come off more than steel.. Can anyone with experience of these
machines point me in any directions to look to? Thanks!


Replace the blade.

Tom
  #5   Report Post  
Posted to rec.crafts.metalworking
John Martin
 
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Default Band saw blade keeps coming off

Line up the wheels. Make sure they are in the same plane.

Crown the tires.

Install a blade with a good weld.

Back off the guides and adjust the wheel tracking so the blade tracks
on the wheel crowns. Adjust the guides.

John Martin



  #6   Report Post  
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Chris
 
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Default Band saw blade keeps coming off

On 26 Jan 2006 14:14:53 -0800, John Martin wrote:

Line up the wheels. Make sure they are in the same plane.

Crown the tires.

Install a blade with a good weld.

Back off the guides and adjust the wheel tracking so the blade tracks
on the wheel crowns. Adjust the guides.

John Martin


Thanks for the replies, what do you mean by "crown the tires" please? The
wheels are flat on the blade running surface and seem to have glued on
abrasive coating, not something that looks to be (easily or cost
effectively) renewable. Cheers.
  #7   Report Post  
Posted to rec.crafts.metalworking
Glenn Ashmore
 
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Default Band saw blade keeps coming off

First check blade weld and make sure it is straight. Next check the rubber
tires. They should have a slight crown. If it has worn flat you need new
tires. Sort of counter intuitive but the blade seeks the high spot as it is
running. Next check the wheel alignment. Both wheels should be parallel
and in the same plane. Lay a straight edge against both wheels. It should
touch the top and bottom rim of both wheels. If not there should be a set
screw or bolt next to the top wheel axel that adjust the angle and the
powered wheel can be slipped in or out on its shaft.

The blade tension should be just tight enough that it makes a musical note
when plucked and it is good practice to back off the tension when the saw is
not being used.

The Bandsaw Book by Mark Duginski is primarily aimed at wood cutting
bandsaws but the tuning chapter applies to both wood and metal.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Chris" wrote in message
...
I feel an idiot for not being able to get this damned thing fixed myself,
but I have a smallish bench mounted metal cutting bandsaw of good quality.
OK, she's done a bit of work before I got her, but there's no wear in the
bearings and the cast iron wheels run true. I have played with blade
tension (tighter seems more reliable) and with the top (none powered
wheel)
tilt, which is adjustable, and the blade guide ball bearings, which are
adjustable, but STILL the blade will suddenly jump off one of the wheels.
3
things look less than perfect. the wheels had some sort o gritty coating,
when new, like coarse carborundum paper, this is now quite worn. The blade
makes a noticeable jump as the welded part passes through the work piece.
Nothing much, but when worked hard it is audible and can be felt. Finally
the blade is quite old and not as sharp as it might be. Cutting alloy
makes
the blade come off more than steel.. Can anyone with experience of these
machines point me in any directions to look to? Thanks!



  #8   Report Post  
Posted to rec.crafts.metalworking
Glenn Ashmore
 
Posts: n/a
Default Band saw blade keeps coming off

Sounds like the tires have been removed. They are thin rubber bands that
are glued to the wheels. They have a slight crown in the center. The crown
forces the blade back to the center of the wheel when it gets off to one
side.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Chris" wrote in message
...
On 26 Jan 2006 14:14:53 -0800, John Martin wrote:

Line up the wheels. Make sure they are in the same plane.

Crown the tires.

Install a blade with a good weld.

Back off the guides and adjust the wheel tracking so the blade tracks
on the wheel crowns. Adjust the guides.

John Martin


Thanks for the replies, what do you mean by "crown the tires" please? The
wheels are flat on the blade running surface and seem to have glued on
abrasive coating, not something that looks to be (easily or cost
effectively) renewable. Cheers.



  #9   Report Post  
Posted to rec.crafts.metalworking
Tom
 
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Default Band saw blade keeps coming off

Glenn Ashmore wrote:

Sounds like the tires have been removed. They are thin rubber bands that
are glued to the wheels. They have a slight crown in the center. The crown
forces the blade back to the center of the wheel when it gets off to one
side.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Chris" wrote in message
...
On 26 Jan 2006 14:14:53 -0800, John Martin wrote:

Line up the wheels. Make sure they are in the same plane.

Crown the tires.

Install a blade with a good weld.

Back off the guides and adjust the wheel tracking so the blade tracks
on the wheel crowns. Adjust the guides.

John Martin


Thanks for the replies, what do you mean by "crown the tires" please? The
wheels are flat on the blade running surface and seem to have glued on
abrasive coating, not something that looks to be (easily or cost
effectively) renewable. Cheers.


It's a metal cutting bandsaw, they don't have rubber tires and the
wheels don't need crowning.
The blade needs replacing before anything else.

Tom
  #10   Report Post  
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John Martin
 
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Default Band saw blade keeps coming off


Tom wrote:

It's a metal cutting bandsaw, they don't have rubber tires and the
wheels don't need crowning.
The blade needs replacing before anything else.

Tom


You sure about that, Tom?

John Martin



  #11   Report Post  
Posted to rec.crafts.metalworking
Tom Gardner
 
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Default Band saw blade keeps coming off


"Tom" wrote in message
...
It's a metal cutting bandsaw, they don't have rubber tires and the
wheels don't need crowning.
The blade needs replacing before anything else.

Tom


There's probably some political thing going on here, if one faction want's
to believe in tires and crowning, who are you to burst the bubble and
suggest the obvious?


  #12   Report Post  
Posted to rec.crafts.metalworking
 
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Default Band saw blade keeps coming off

What is the size of this bandsaw, is it two wheel or a smaller three
wheel. Does fly off when cutting wood or metal, well it stay on when
cutting wood but fly off when you try to cut metal?

  #13   Report Post  
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Tom
 
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Default Band saw blade keeps coming off

John Martin wrote:

Tom wrote:

It's a metal cutting bandsaw, they don't have rubber tires and the
wheels don't need crowning.
The blade needs replacing before anything else.

Tom


You sure about that, Tom?

John Martin


Yes
  #14   Report Post  
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Tom
 
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Default Band saw blade keeps coming off

Tom Gardner wrote:

"Tom" wrote in message
...
It's a metal cutting bandsaw, they don't have rubber tires and the
wheels don't need crowning.
The blade needs replacing before anything else.

Tom


There's probably some political thing going on here, if one faction want's
to believe in tires and crowning, who are you to burst the bubble and
suggest the obvious?


Ya right, better retread the wheels, crown them, fit new bearings,
guides, possibly rewind the motor and replace the switch.
To actually suggest replacing a consumable before overhauling
the machine was unthinkable.
Thanks for the headsup Tom, I withdraw all previous suggestions
as totally inappropriate. Hang on a minute, didn't I read somewhere,
that you suggested replacing the blade?

Tom
  #15   Report Post  
Posted to rec.crafts.metalworking
John Martin
 
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Default Band saw blade keeps coming off


Tom wrote:
John Martin wrote:

Tom wrote:

It's a metal cutting bandsaw, they don't have rubber tires and the
wheels don't need crowning.
The blade needs replacing before anything else.

Tom


You sure about that, Tom?

John Martin


Yes


You might want to write to DoAll and Grob and a few others, then, and
tell them that they're wasting money by putting tires on their wheels.
Oh, wait, those must be woodworking saws. Silly me.

It probably is the blade. But there are a lot of other things he
should be checking.

John Martin



  #17   Report Post  
Posted to rec.crafts.metalworking
Harold and Susan Vordos
 
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Default Band saw blade keeps coming off


"Tom" wrote in message
...
snip----

It's a metal cutting bandsaw, they don't have rubber tires and the
wheels don't need crowning.
The blade needs replacing before anything else.

Tom


What Tom said. The typical horizontal band saw has no crown, nor rubber
tire. They typically have a shoulder, against which the back of the blade
runs. If the wheels are properly aligned with one another, the blade will
stay in place. A tired, old blade often will come off time and again.
You can usually attribute the problem to minor dissimilar stretch of the
blade. Try a new blade before anything else.

Harold


  #18   Report Post  
Posted to rec.crafts.metalworking
Tom Gardner
 
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Default Band saw blade keeps coming off

There's probably some political thing going on here, if one faction
want's
to believe in tires and crowning, who are you to burst the bubble and
suggest the obvious?


Ya right, better retread the wheels, crown them, fit new bearings,
guides, possibly rewind the motor and replace the switch.
To actually suggest replacing a consumable before overhauling
the machine was unthinkable.
Thanks for the headsup Tom, I withdraw all previous suggestions
as totally inappropriate. Hang on a minute, didn't I read somewhere,
that you suggested replacing the blade?

Tom


I was laughing so hard, my laptop hit the floor and I can't see through the
tears.


  #19   Report Post  
Posted to rec.crafts.metalworking
Tom Gardner
 
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Default Band saw blade keeps coming off


"Harold and Susan Vordos"
wrote in message ...
What Tom said. The typical horizontal band saw has no crown, nor rubber
tire. They typically have a shoulder, against which the back of the blade
runs. If the wheels are properly aligned with one another, the blade
will
stay in place. A tired, old blade often will come off time and again.
You can usually attribute the problem to minor dissimilar stretch of the
blade. Try a new blade before anything else.

Harold


Harold, SHUT UP they don't want to hear it! Except for poor Chris.


  #21   Report Post  
Posted to rec.crafts.metalworking
Harold and Susan Vordos
 
Posts: n/a
Default Band saw blade keeps coming off


"Tom Gardner" wrote in message
news

"Harold and Susan Vordos"
wrote in message ...
What Tom said. The typical horizontal band saw has no crown, nor rubber
tire. They typically have a shoulder, against which the back of the

blade
runs. If the wheels are properly aligned with one another, the blade
will
stay in place. A tired, old blade often will come off time and again.
You can usually attribute the problem to minor dissimilar stretch of the
blade. Try a new blade before anything else.

Harold


Harold, SHUT UP they don't want to hear it! Except for poor Chris.

**** on ya', Tom! g

Harold



  #22   Report Post  
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Tom
 
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Default Band saw blade keeps coming off

Tom Gardner wrote:

On the same note as this bandsaw, I'm having a problem with my Arter
grinder. The wheel is worn down to the label and it just isn't cutting
right anymore...What should I do?


Fit a new stator to up the rpm to attain optimum grinding speed.
A new lick of paint, cord and plug. As a last resort, remove the
label lest it impede grinding..

Tom
  #23   Report Post  
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Tom Gardner
 
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Default Band saw blade keeps coming off

On the same note as this bandsaw, I'm having a problem with my Arter
grinder. The wheel is worn down to the label and it just isn't cutting
right anymore...What should I do?


  #25   Report Post  
Posted to rec.crafts.metalworking
Harold and Susan Vordos
 
Posts: n/a
Default Band saw blade keeps coming off


"Tom Gardner" wrote in message
. com...
On the same note as this bandsaw, I'm having a problem with my Arter
grinder. The wheel is worn down to the label and it just isn't cutting
right anymore...What should I do?

Have you tried hitting it with one of your wire brushes?

Harold





  #26   Report Post  
Posted to rec.crafts.metalworking
Harold and Susan Vordos
 
Posts: n/a
Default Band saw blade keeps coming off


"Tom" wrote in message
...
Tom Gardner wrote:

On the same note as this bandsaw, I'm having a problem with my Arter
grinder. The wheel is worn down to the label and it just isn't cutting
right anymore...What should I do?


Fit a new stator to up the rpm to attain optimum grinding speed.
A new lick of paint, cord and plug. As a last resort, remove the
label lest it impede grinding..

Tom


Yep! I agree. What Tom said! g

Harold


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Chris
 
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Default Band saw blade keeps coming off

On Thu, 26 Jan 2006 22:21:53 +0000, Chris wrote:

Thanks for the replies, didn't mean to start another war I'll get a
couple of blades welded up, and see what happens. How many TPI should I
get, one for cutting ali plate / blocks, the other for (say) 1/8 inch mild
steel plate? Thanks for all the answers and the laughs
  #28   Report Post  
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Tom Gardner
 
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Default Band saw blade keeps coming off

Oh great! Now your going to start ANOTHER religious war!

Seriously, the last time I bought blades for my vertical I told my supplier
to ship six of each style he had. The bill was maybe $200 but that was one
situation that totally went away. I have a welder and have also bought
partial stock spools when the suppliers are running a clearance sale,
usually at about 25 cents a foot. (the old rule of thumb: "3 teeth in the
work min.")

"Chris" wrote in message
. ..
On Thu, 26 Jan 2006 22:21:53 +0000, Chris wrote:

Thanks for the replies, didn't mean to start another war I'll get a
couple of blades welded up, and see what happens. How many TPI should I
get, one for cutting ali plate / blocks, the other for (say) 1/8 inch mild
steel plate? Thanks for all the answers and the laughs



  #29   Report Post  
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Dave Hinz
 
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Default Band saw blade keeps coming off

On 26 Jan 2006 15:47:20 -0800, John Martin wrote:

Tom wrote:

It's a metal cutting bandsaw, they don't have rubber tires and the
wheels don't need crowning.
The blade needs replacing before anything else.


You sure about that, Tom?


I'm sure my metal-cutting saw has tires, because I checked last night.

  #30   Report Post  
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Harold and Susan Vordos
 
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Default Band saw blade keeps coming off


"Dave Hinz" wrote in message
...
On 26 Jan 2006 15:47:20 -0800, John Martin wrote:

Tom wrote:

It's a metal cutting bandsaw, they don't have rubber tires and the
wheels don't need crowning.
The blade needs replacing before anything else.


You sure about that, Tom?


I'm sure my metal-cutting saw has tires, because I checked last night.


Saws that accommodate various blade sizes tend to have rubber tires, so the
blade can be run without damage to wheel or blade. In that case, the top
wheel is generally adjustable so the blade will track where desired. Saws
that run only a dedicated blade size normally do not. In that case, the
size of the wheel where the blade runs is such that the teeth run with
clearance (the edge of the wheel), back of the blade against the shoulder of
the wheel. The shoulder is lacking on rubber tired wheels, so the blade is
free to seek proper location, determined by the blade support at the point
of the cut. Canting the adjustable top wheel makes the necessary
adjustment.. Yes, I'm aware that there are likely some variations on what
I've said.

Harold




  #31   Report Post  
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Harold and Susan Vordos
 
Posts: n/a
Default Band saw blade keeps coming off


"Tom Gardner" wrote in message
. com...
Oh great! Now your going to start ANOTHER religious war!

Seriously, the last time I bought blades for my vertical I told my

supplier
to ship six of each style he had. The bill was maybe $200 but that was

one
situation that totally went away. I have a welder and have also bought
partial stock spools when the suppliers are running a clearance sale,
usually at about 25 cents a foot. (the old rule of thumb: "3 teeth in the
work min.")

"Chris" wrote in message
. ..
On Thu, 26 Jan 2006 22:21:53 +0000, Chris wrote:

Thanks for the replies, didn't mean to start another war I'll get a
couple of blades welded up, and see what happens. How many TPI should I
get, one for cutting ali plate / blocks, the other for (say) 1/8 inch

mild
steel plate? Thanks for all the answers and the laughs



What Tom said, but keep in mind that speed plays a big role in how a blade
performs. For example, you can saw thin aluminum very successfully with a
4 pitch blade, assuming you're running the blade quite fast. If you run
within recommended surface speeds, the blade you select should always have
three or more teeth in contact with the material at one time, otherwise it's
possible for the material to overfeed, shearing teeth from the blade. That
happens easily when sawing materials like sheet stainless steel, but common
sheet steel will do it as well.

The other thing to keep in mind is the size of the material being sawed, or
the length of the cut. When you use a blade that has way too many teeth in
contact, the blade loads to the point where the gullet can no longer
accommodate any more chip, then it floats the blade. Not only does your cut
slow way down, but you wear the blade prematurely, because it's not cutting,
but dragging instead. With a carbon steel blade, you risk warming the blade
to the point of annealing it under that condition. In the case of a long
cut, use a coarse blade, even one as coarse as 4 TPI, even in steel.

If you're sawing shapes (angle, channel, pipe or tubing), the thin sections
will dictate the pitch of the blade. If you expect good performance from
your saw, have various blade types at your disposal, and change the blade
when the cut isn't within reasonable parameters. You'll be much happier
with how your saw performs.

Harold


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Chris
 
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Default Band saw blade keeps coming off

On Fri, 27 Jan 2006 12:07:27 -0800, Harold and Susan Vordos wrote:


What Tom said, but keep in mind that speed plays a big role in how a blade
performs. For example, you can saw thin aluminum very successfully with a


snip

Great info, everyone. I am learning a great deal from this news group. Many
thanks for such detailed replies.
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Chris
 
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Default Band saw blade keeps coming off

On Thu, 26 Jan 2006 17:26:19 -0500, Glenn Ashmore wrote:

First check blade weld and make sure it is straight. Next check the rubber


snip

Thanks, some good info. I hadn't realized the powered wheel would slide on
the shft, by design. It's in line though, and both are perpendicular to one
another.
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